<title>局域网</title><link href="http://hzoi.com/tomorrow.css" rel="stylesheet"><div class="ui existing segment"><pre><code><span class="pl-cp">#include</span> <span class="pl-cpf">&lt;cstdio&gt;</span><span class="pl-cp"></span>
<span class="pl-cp">#include</span><span class="pl-cpf">&lt;iostream&gt;</span><span class="pl-cp"></span>
<span class="pl-cp">#include</span><span class="pl-cpf">&lt;algorithm&gt;</span><span class="pl-cp"></span>
<span class="pl-cp">#define MAXN 105</span>
<span class="pl-k">using</span> <span class="pl-k">namespace</span> <span class="pl-n">std</span><span class="pl-p">;</span>
<span class="pl-k">struct</span> <span class="pl-n">edge</span><span class="pl-p">{</span>
    <span class="pl-kt">int</span> <span class="pl-n">a</span><span class="pl-p">,</span><span class="pl-n">b</span><span class="pl-p">,</span><span class="pl-n">w</span><span class="pl-p">;</span>
    <span class="pl-kt">bool</span> <span class="pl-k">operator</span><span class="pl-o">&lt;</span><span class="pl-p">(</span><span class="pl-n">edge</span> <span class="pl-n">b</span><span class="pl-p">)</span><span class="pl-k">const</span><span class="pl-p">{</span><span class="pl-k">return</span> <span class="pl-n">w</span><span class="pl-o">&lt;</span><span class="pl-n">b</span><span class="pl-p">.</span><span class="pl-n">w</span><span class="pl-p">;}</span>
<span class="pl-p">}</span> <span class="pl-n">edges</span><span class="pl-p">[</span><span class="pl-n">MAXN</span><span class="pl-p">];</span>
<span class="pl-kt">int</span> <span class="pl-n">f</span><span class="pl-p">[</span><span class="pl-n">MAXN</span><span class="pl-p">];</span>
<span class="pl-kt">int</span> <span class="pl-nf">find</span><span class="pl-p">(</span><span class="pl-kt">int</span> <span class="pl-n">x</span><span class="pl-p">){</span><span class="pl-k">return</span> <span class="pl-n">f</span><span class="pl-p">[</span><span class="pl-n">x</span><span class="pl-p">]</span><span class="pl-o">==</span><span class="pl-n">x</span><span class="pl-o">?</span><span class="pl-nl">x</span><span class="pl-p">:(</span><span class="pl-n">f</span><span class="pl-p">[</span><span class="pl-n">x</span><span class="pl-p">]</span><span class="pl-o">=</span><span class="pl-n">find</span><span class="pl-p">(</span><span class="pl-n">f</span><span class="pl-p">[</span><span class="pl-n">x</span><span class="pl-p">]));}</span>
<span class="pl-kt">void</span> <span class="pl-nf">join</span><span class="pl-p">(</span><span class="pl-kt">int</span> <span class="pl-n">a</span><span class="pl-p">,</span><span class="pl-kt">int</span> <span class="pl-n">b</span><span class="pl-p">){</span><span class="pl-n">f</span><span class="pl-p">[</span><span class="pl-n">find</span><span class="pl-p">(</span><span class="pl-n">a</span><span class="pl-p">)]</span><span class="pl-o">=</span><span class="pl-n">find</span><span class="pl-p">(</span><span class="pl-n">b</span><span class="pl-p">);}</span>
<span class="pl-kt">int</span> <span class="pl-nf">main</span><span class="pl-p">(){</span>
    <span class="pl-kt">int</span> <span class="pl-n">n</span><span class="pl-p">,</span><span class="pl-n">k</span><span class="pl-p">,</span><span class="pl-n">sum</span><span class="pl-o">=</span><span class="pl-mi">0</span><span class="pl-p">,</span><span class="pl-n">t1</span><span class="pl-p">,</span><span class="pl-n">t2</span><span class="pl-p">,</span><span class="pl-n">t3</span><span class="pl-p">;</span>
    <span class="pl-n">scanf</span><span class="pl-p">(</span><span class="pl-s">&quot;%d%d&quot;</span><span class="pl-p">,</span><span class="pl-o">&amp;</span><span class="pl-n">n</span><span class="pl-p">,</span><span class="pl-o">&amp;</span><span class="pl-n">k</span><span class="pl-p">);</span>
    <span class="pl-k">for</span><span class="pl-p">(</span><span class="pl-kt">int</span> <span class="pl-n">i</span><span class="pl-o">=</span><span class="pl-mi">1</span><span class="pl-p">;</span><span class="pl-n">i</span><span class="pl-o">&lt;=</span><span class="pl-n">n</span><span class="pl-p">;</span><span class="pl-n">i</span><span class="pl-o">++</span><span class="pl-p">)</span><span class="pl-n">f</span><span class="pl-p">[</span><span class="pl-n">i</span><span class="pl-p">]</span><span class="pl-o">=</span><span class="pl-n">i</span><span class="pl-p">;</span>
    <span class="pl-k">for</span><span class="pl-p">(</span><span class="pl-kt">int</span> <span class="pl-n">i</span><span class="pl-o">=</span><span class="pl-mi">1</span><span class="pl-p">;</span><span class="pl-n">i</span><span class="pl-o">&lt;=</span><span class="pl-n">k</span><span class="pl-p">;</span><span class="pl-n">i</span><span class="pl-o">++</span><span class="pl-p">){</span>
        <span class="pl-n">scanf</span><span class="pl-p">(</span><span class="pl-s">&quot;%d%d%d&quot;</span><span class="pl-p">,</span><span class="pl-o">&amp;</span><span class="pl-n">t1</span><span class="pl-p">,</span><span class="pl-o">&amp;</span><span class="pl-n">t2</span><span class="pl-p">,</span><span class="pl-o">&amp;</span><span class="pl-n">t3</span><span class="pl-p">);</span>
        <span class="pl-n">sum</span><span class="pl-o">+=</span><span class="pl-n">t3</span><span class="pl-p">;</span>
        <span class="pl-n">edges</span><span class="pl-p">[</span><span class="pl-n">i</span><span class="pl-p">].</span><span class="pl-n">a</span><span class="pl-o">=</span><span class="pl-n">t1</span><span class="pl-p">;</span>
        <span class="pl-n">edges</span><span class="pl-p">[</span><span class="pl-n">i</span><span class="pl-p">].</span><span class="pl-n">b</span><span class="pl-o">=</span><span class="pl-n">t2</span><span class="pl-p">;</span>
        <span class="pl-n">edges</span><span class="pl-p">[</span><span class="pl-n">i</span><span class="pl-p">].</span><span class="pl-n">w</span><span class="pl-o">=</span><span class="pl-n">t3</span><span class="pl-p">;</span>
    <span class="pl-p">}</span>
    <span class="pl-kt">int</span> <span class="pl-n">tsum</span><span class="pl-o">=</span><span class="pl-mi">0</span><span class="pl-p">,</span><span class="pl-n">ti</span><span class="pl-o">=</span><span class="pl-mi">0</span><span class="pl-p">;</span>
    <span class="pl-n">sort</span><span class="pl-p">(</span><span class="pl-n">edges</span><span class="pl-o">+</span><span class="pl-mi">1</span><span class="pl-p">,</span><span class="pl-n">edges</span><span class="pl-o">+</span><span class="pl-n">k</span><span class="pl-o">+</span><span class="pl-mi">1</span><span class="pl-p">);</span>
    <span class="pl-k">for</span><span class="pl-p">(</span><span class="pl-kt">int</span> <span class="pl-n">i</span><span class="pl-o">=</span><span class="pl-mi">1</span><span class="pl-p">;</span><span class="pl-n">i</span><span class="pl-o">&lt;=</span><span class="pl-n">k</span><span class="pl-p">;</span><span class="pl-n">i</span><span class="pl-o">++</span><span class="pl-p">){</span>
        <span class="pl-kt">int</span> <span class="pl-n">a</span><span class="pl-o">=</span><span class="pl-n">edges</span><span class="pl-p">[</span><span class="pl-n">i</span><span class="pl-p">].</span><span class="pl-n">a</span><span class="pl-p">,</span><span class="pl-n">b</span><span class="pl-o">=</span><span class="pl-n">edges</span><span class="pl-p">[</span><span class="pl-n">i</span><span class="pl-p">].</span><span class="pl-n">b</span><span class="pl-p">,</span><span class="pl-n">w</span><span class="pl-o">=</span><span class="pl-n">edges</span><span class="pl-p">[</span><span class="pl-n">i</span><span class="pl-p">].</span><span class="pl-n">w</span><span class="pl-p">;</span>
        <span class="pl-k">if</span><span class="pl-p">(</span><span class="pl-n">find</span><span class="pl-p">(</span><span class="pl-n">a</span><span class="pl-p">)</span><span class="pl-o">==</span><span class="pl-n">find</span><span class="pl-p">(</span><span class="pl-n">b</span><span class="pl-p">))</span><span class="pl-k">continue</span><span class="pl-p">;</span>
        <span class="pl-c1">//printf(&quot;[%d %d]\n&quot;,a,b);</span>
        <span class="pl-n">join</span><span class="pl-p">(</span><span class="pl-n">a</span><span class="pl-p">,</span><span class="pl-n">b</span><span class="pl-p">);</span>
        <span class="pl-n">tsum</span><span class="pl-o">+=</span><span class="pl-n">w</span><span class="pl-p">;</span>
        <span class="pl-n">ti</span><span class="pl-o">++</span><span class="pl-p">;</span>
        <span class="pl-k">if</span><span class="pl-p">(</span><span class="pl-n">ti</span><span class="pl-o">==</span><span class="pl-n">n</span><span class="pl-o">-</span><span class="pl-mi">1</span><span class="pl-p">)</span><span class="pl-k">break</span><span class="pl-p">;</span>
    <span class="pl-p">}</span>
    <span class="pl-n">printf</span><span class="pl-p">(</span><span class="pl-s">&quot;%d&quot;</span><span class="pl-p">,</span><span class="pl-n">sum</span><span class="pl-o">-</span><span class="pl-n">tsum</span><span class="pl-p">);</span>
<span class="pl-p">}</span>
</cpde></pre></div>